engleski

Sustainability of the water resources in the National Park Plitvice Lakes

The National Park Plitvice Lakes (NPPL) has been placed in the central part of Croatia, in Dinaric karst region. Plitvice lakes are one of the most remarkable and attractive karst features in Croatia with the status of national park from 1949 and maintain a prominent place on the UNESCO list of World Heritage of Nature from 1979. With huge karst springs, numerous lakes separated by tufa barriers and hundreds of waterfalls, together with extraordinary biodiversity is a unique natural ambience, attracting up to the nearly one million visitors yearly. The discharge area of the lakes is placed on the northern side of the Dinaric carbonate platform in the Lika region and belongs to the Danube catchment area. One of the most important questions is the protection of water resources, because only high water quality can ensure the sustainability of entire eco-system. The research programme have had three main goals - protection of the main karst springs of Plitvice lakes from the catchment, protection of the lakes and waterfalls burdened by the great number of visitors, and protection of wider karst environment from NPPL. The entire area of NPPL is built from carbonate rocks. The tectonic picture is very complex with prevailing NW-SE direction of dominant faults. An important hydrogeological role in the recharge zone has the anticlinal form of Mala Kapela Mountain, in discharge and lakes zone so called penetration tectonic structure built from dolomites and in sinking zone the synclinal structure of Lička Plješivica Mountain. Dolomites are the hydrogeological barrier for groundwater flowing from karst high permeable aquifer of Mala Kapela Mountain. After discharge zone, water flows over the barrier toward the strong longitudinal fault on the NE side of the largest Kozjak Lake practically without any water loss. Passing the fault zone begin the gradual sinking, which at least is manifested with complete drying of Korana River downstream of the administrative border of NPPL. Groundwater from the catchment area, of about 150 km2, flow toward the spring zone with relatively high apparent velocities, what is the indicator of low retention capability of karst aquifer and high vulnerability of the catchment. Hydrogeochemical investigations had very important role in the identification of water dynamic model of the system. That is very important for the oxygen enrichment of water in the bottom parts of lakes and maintenance of the water quality of entire eco-system. Hydrogeological investigations have opened the problem of naturally high vulnerable Kozjak Lake. Existing of the lake depends of the changeable thickness of tufa sediments, which cover the fault zone and fill the caverns and cracks in karstified limestones. The research results have pointed out several important facts and problems which have to be solved urgently, but in spite of that the water resources in NPPL are in very good condition. In definition of protection scheme of Plitvice Lakes were used the adapted EU methodology (COST 620) with the combined vulnerability, hazard and risk analyses and the elements of Croatian regulation for the definition of protection zones in karst areas.

Plitvice Lakes; genesis of water system; water dynamics; water protection; water management

nije evidentirano